I think I agree with every word Gaffer Tape has said, both with relation to the films and the cartoons.
To give the cartoons some credit, I believe there was an episode where he was going to receive corrective surgery and simultaneously eliminate his evil side, which gave his character more of a motive. But I hear what you're saying: the origins were fascinating, and then the bad guys just became another baddie with his/her own gimmick.